Erythema infectiosum (Fifth disease)

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2 Erythema infectiosum (Fifth disease)

3 Parvovirinae Parvovirus B19 Bocaviruses

4 Erythema Infectiosum (fifth disease) Arthritis Transient Aplastic Crisis in chronic hemolytic anemia Chronic anemia in immunodeficiency syndrome Hydrops fetalis

5 Caused by Parvovirus B19 Affects preschool and young school aged children Peak incidence in late winter and early spring, but it is seen year round Characterized by rash - large, bright red, erythematous patches over both cheeks - warm, but non-tender

6 Fifth disease is a mild rash illness that occurs most commonly in children An ill child may have a low-grade fever, malaise, or a "cold" a few days before the rash breaks out The child is usually not very ill, and the rash resolves in 7 to 10 days.

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9 Transmission of infection occurs via: respiratory secretions (e.g., saliva, sputum, or nasal mucus) The virus is probably spread from person to person by direct contact with those secretions blood-derived products administered parenterally vertically from mother to fetus

10 How soon after infection with parvovirus B19 does a person become ill A susceptible person usually becomes ill 4 to 14 days after being infected with the virus, but may become ill for as long as 20 days after infection. Does everyone who is infected with parvovirus B19 become ill? No. During outbreaks of fifth disease, about 20% of adults and children who are infected with parvovirus B19 do not develop any symptoms. Furthermore, other persons infected with the virus will have a non-specific illness that is not characteristic of fifth disease. Persons infected with the virus, however, do develop lasting immunity that protects them against infection in the future.

11 Is fifth disease serious? - Fifth disease is usually a mild illness that resolves on its own among children and adults who are otherwise healthy. -Parvovirus B19 infection may cause a serious illness in persons with sickle-cell disease or similar types of chronic anemia. -People who have leukemia or cancer, who are born with immune deficiencies, who have received an organ transplant, or who have human immunodeficiency virus (HIV) infection are at risk for serious illness due to parvovirus B19 infection. -Occasionally, serious complications may develop from parvovirus B19 infection during pregnancy.

12 Can parvovirus B19 infection be prevented? There is no vaccine or medicine that prevents parvovirus B19 infection. Frequent handwashing is recommended as a practical and probably effective method to decrease the chance of becoming infected. Excluding persons with fifth disease from work, child care centers, or schools is not likely to prevent the spread of the virus, since people are contagious before they develop the rash.

13 Enzyme Immunoassay IgM (EIA) Radioimmunoassay IgM (RIA) DNA Hybridization PCR

14 Result IgG+ IgM- IgG- IgMinfection IgG+ or - infection. IgM equivocal IgG+ igm+ IgG- or equivocal IgM+ Interpretation Implies Past Exposeur / Infection Minimal risk of parvovirus B19 infectioni Implies no past infection Patient may be susceptible to parvovirus B19 May be indicative of a current or recent Resample within 1 or 2 weeks and retest Implies current or recent infection Fetus may be at risk may be indicative of a current infection. Resample within 1 to 2 weeks and retest.

15 human bocavirus (HBoV) hbov belongs to the genus Bocavirus in the subfamily parvovirinae of the family parvoviridae and is most closely related to bovine parvovirus and minute virus of canines. Therefore, it was named human bocavirus (HBoV). Subsequently,HBoV has been detected frequently in children with respiratory tract infections and asthma exacerbation worldwide. Recently, HBoV has also been implicated in diarrhea, and its detection rates in children with gastroenteritis have a range of 0.8% 9.1%.

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21 Roseola (Exanthema Subitum) sixth disease

22 Subfamily Growth & Cytopatholog y Latent infection s Genus Official name (herpes virus) Commo n name Alphaherpesvirinae Short, cytolytic Neurons Simplexvirus 1 2 HSV-1 HSV-2 Varicellvirus 3 VZV Betaherpesvirinae Long, cytomegalic Glands, kidneys Cytomegalovirus 5 CMV Long, lymphoprolife rative Lymphoi d tissue Roseolovirus 6 7 HHV-6 HHV-7 Gammaherpesvirina e Long, lymphoproliferat ive Lymphoid tissue Lymphocryptoviru s 4 EBV Rhadinovirus 8 Kaposi sarcoma virus 22

23 Viral DNA kbp The genetic arrangement resembles CMV Two antigenic group: A, B Virus grows in CD4 T, B lymphocytes, glial cell, fibroblasts and megakaryocyte CD46 is the cellular receptor for virus

24 Infections occur in infancy: exanthem subitum (Roseola infantum ) Febrile illness affecting children 6-36 months Human herpesvirus 6 is causative agent Symptoms include: fever, usually >39 anorexia irritability these symptoms subside in 72 hours

25 As fever defervenscences, usually an erythematous, maculopapular rash that appear on the trunk and then spread to the extremities, face, scalp, and neck Occurs year-round More common in late fall and early spring Incubation period thought to be days Infection persist for life Transmission via oral secretion

26 It is present in most brains. Congenital transmission is possible The seroprevalence is >90% There is possible pathogenic interaction with other viruses. It is frequently misdiagnosed or not diagnosed at all. It is associated with a wide range of diseases. Most commonly associated with primary HHV-6B infection % of cases due to HHV % cases are unapparent.

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28 Blood Sample Methods: Collection Processing within 24 hrs. Ficoll-Paque Separation Whole Blood Lymphocytes Plasma RNA Extractions DNA Extraction ELISA (IgM, IgG) 10ul RT-PCR -Light Cycler- U38 Primers and Probes Qualitative PCR U38 Primers Viral Quantification (if+) -Light Cycler- U38 Primers and Probes IgG Avidity

29 paramyxovirinae PRAMYXOVIRIDAE Two sub- families Pneumovirinae

30 Property Paramyxovirinae Pneumovirinae Respiro Rubula Morbilli Pneumo metapneumo Human viruses Parainfluenza 1,3 Mumps, parainfluenza 2,4a,4b Measles RSV Human metapneumo virus Serotypes 1 each 1 each 1 2?? F Prot Haemolysin HA NA NO HAEMOLYIN NO HA NO NA NO NA

31 TYPE 1,2,& 3 are particularly considered major pathogens of severe respiratory tract disease in infants & young children. HPIV-1 is the leading cause of croup in children, whereas HPIV-2 is less frequently detected. HPIV-3 is more often associated with bronchiolitis and pneumonia. age 6-18 month incubation period 2 to 7 days Type 4 does not cause severe disease even on primary infection. two subtypes (4a and 4b).

32 Human Parainfluenza Viruses Epidemiologic Features HPIVs are spread person to person by direct contact with infected secretions through respiratory droplets or contaminated surfaces or objects. Infection can occur when infectious material contacts mucous membranes of the eyes, mouth, or nose, and possibly through the inhalation of droplets generated by a sneeze or cough. HPIVs can remain infectious in airborne droplets for over an hour.

33 Diagnosis Infection with HPIVs can be confirmed in various ways: 1) by isolation and identification of the virus in cell culture 2)by direct detection of viral antigens in respiratory secretions by use of immunofluorescence, enzyme immunoassay 3)by polymerase chain reaction assay 4)by demonstration of a significant rise in specific IgG antibodies between appropriately collected paired serum specimens, although infection may not always elicit a significant antibody response.

34 Old name mean (to mope depressed persons) Acute viral infection that primary infect parotid gland Immunity is life-long after a case of mumps 1/3 sub clinical

35 Inoculation of URT Local replication Viremia Systemic infection pancreas Testes Ovaries Peripheral nerves Eye Inner ear CNS Parotid gland Virus multiplies in ductal epithelial cells. local inflammation causes Marked swelling

36 Mumps is infectious for 2-7 days before the symptoms and for approximately 9-10 days after the appearance of the symptoms.

37 Often asymptomatic Malaise and fever followed (24h) Redness, swelling of parotid gland duct (Parotitis) Swelling of other glands

38 Complication The most common complication is inflammation of the testicles (orchitis) in males who have reached puberty; rarely does this lead to fertility problems.swelling of orchitis cause sterility (20%) 2-5 days after parotitis. Inflammation of the ovaries (oophoritis) and/or breasts (mastitis) in females who have reached puberty. Menengoencephalitis may occur 50% may involve CNS Deafness

39 Mumps is spread by droplets of saliva or mucus from the mouth, nose, or throat of an infected person, usually when the person coughs, sneezes, or talks In addition, the virus may spread when someone with mumps touches items or surfaces without washing their hands Most mumps transmission likely occurs before the salivary glands begin to swell and up to 5 days after the swelling begins

40 Mumps clinical presentation

41 Samples for serologic testing Serology (serum) samples The first (acute-phase) serum sample should be collected as soon as possible upon suspicion of mumps disease. Collect 7 10 ml of blood serum samples should be collected about 2 3 weeks after the acute-phase sample. Store specimens at 4 C and ship on wet ice packs.

42 Samples for viral detection Oral or buccal swab samples Collect oral or buccal swab samples as soon as mumps disease is suspected. Samples collected when the patient first presents with symptoms have the best chance of having a positive result by RT-PCR. A commercial product designed for the collection of throat specimens or a flocked polyester fiber swab can be used. Synthetic swabs are preferred over cotton swabs, which may contain substances that are inhibitory to enzymes used in RT-PCR. Flocked synthetic swabs appear to be more absorbent and elute samples more efficiently. Swabs should be placed in 2 ml of standard viral transport medium (VTM). Allow the swab to remain in VTM for at least 1 hour (4 C).

43 Urine specimens Urine samples have not been as useful as buccal and oral specimens for virus isolation or detection of mumps RNA. Unlike buccal and oral specimens, urine samples may not be positive for mumps virus until >4 days after symptom onset. A minimum volume of 50 ml of urine should be collected in a sterile container and then processed by centrifuging at 2500 g for 15 minutes at 4 C. The sediment should be resuspended in 2 ml of VTM.

44 Symptoms Rash that starts on the face and neck, then spreads High fever, Runny nose, Red, watery eyes, Cough Tiny white spots with bluish-white centers found inside the mouth (Koplik s spots) Transmission Measles virus is spread easily Through air by coughs or sneezes By direct contact with nose or throat secretions Serious and highly contagious Usually found in non-immunized or partially-immunized (single vaccine, no booster)

45 About 30% of measles cases develop one or more complications, including: Pneumonia, which is the complication that is most often the cause of death in young children. Ear infections occur in about 1 in 10 measles cases and permanent loss of hearing can result. Diarrhea is reported in about 8% of cases. These complications are more common among children under 5 years of age and adults over 20 years old. encephalitis,about one out of 1,000 gets encephalitis, and one or two out of 1,000 die. Other rash-causing diseases often confused with measles include roseola (roseola infantum) and rublla (German measles).

46 SSPE is a very rare, but fatal degenerative disease of the central nervous system that results from a measles virus infection acquired earlier in life. This is compared to 1.1 per 100,000 in those infected after 5 years of age. On average, the symptoms of SSPE begin 7 to 10 years after measles infection, but they can appear anytime from 1 month to 27 years after infection. The diagnosis of SSPE is based on signs and symptoms and on test results, such as typical changes observed in: electroencephalographs, elevated anti-measles antibody (IgG) in the serum and cerebrospinal fluid and typical histologic findings in brain biopsy tissue.

47 Measles pathogenesis Lymphatic spread Virus- infected endothelial cells+ immune T cell Wide dissemination

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49 Measles Koplik Spots

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51 Serum specimens for measles serologic testing (IgG, IgM) arrive at CDC through the Data and Specimen Handling Section (DASH) from international, state, and local health departments, and WHO reference laboratories. Do not freeze the tube before serum has been removed. Centrifuge the tube to separate serum from clot. Aseptically transfer serum to a sterile tube that has an externally threaded cap with an o-ring seal. Fresh, sterile serum can be shipped overnight on wet ice pack. Hemolyzed and lipemic serum and plasma are noted and tested; usually without apparent interferences.

52 Throat or nasopharyngeal swabs are generally the preferred sample for virus isolation or RT-PCR detection. Urine samples may also contain virus and when feasible to do so, collection of both respiratory and urine samples can increase the likelihood of detecting virus. Measles virus isolation is most successful when samples are collected on the first day of rash through 3 days following onset of rash; however, it is possible to detect virus up to day 7 following rash onset.

53 Respiratory Samples For throat, nasopharyngeal or nasal swabs that are in very little fluid (1-4ml), the entire sample can be frozen at -70 C or if low temperature freezers are not available, keep the sample at 4 C until shipment. Urine Samples Virus can be present in the urine even a few days before rash appears and begins to diminish a few days following rash. For optimal virus preservation, centrifuge 10-50ml of urine and resuspend the sediment in 2-3 ml of sterile transport medium, tissue culture medium or physiological buffered saline. Freeze the resuspended urine sample at - 70 C or keep the urine sample at 4 C and ship on cold packs as soon as possible to a laboratory that is able to perform viral isolation.

54 Antibody detection is the most versatile and commonly used method for measles diagnosis A positive test result for specific IgG antibodies in a single serum specimen indicates past infection with measles virus or measles vaccination, but does not ensure protection from infection or reinfection. Detection of specific IgM antibodies in a single serum specimen collected within the first few days of rash onset can provide a good presumptive diagnosis of current or recent measles virus infection. Therefore, the IgM assay is the test of choice for rapid diagnosis of measles cases. The enzyme immunoassay (EIA) is the most commonly used method for detecting measles-specific IgM and IgG antibodies

55 1. Genus pneumovirus which include respiratory syncytial virus RSV 2. Genus metapneumovirus which include: human metapneumovirus

56 Family Paramyxoviridae Genus Pneumovirus Subgroups A and B

57 nm enveloped virus Spherical or pleomorphic shape Single stranded negative sense RNA 2 non-structural and 8 structural proteins

58 RSV is transmitted via droplet infection. Such droplets can linger briefly in the air, and if someone inhales the particles or the particles contact their nose, mouth, or eye, they can become infected. Infection can also result from direct and indirect contact with nasal or oral secretions from infected Viral replication occurs in the epithelial cells of the nasopharynx. Viremia has not been detected.

59 RSV is the most important cause of LRT illness in infants and young children. When infants and children are exposed to RSV for the first time, 25% to 40% of them have signs or symptoms of bronchiolitis or pneumonia, and 0.5% to 2% will require hospitalization. Most children hospitalized for RSV infection are under 6 months of age. It is the main cause of: Bronhiolitis (about 50%) Pneumonia (25%) under one year of age.

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61 Viral shedding usually lasts 3-6 days, with a range of 1 to 12 days In patients with underlying malignancy and suppressive chemotherapy, prolonged viral shedding is seen. the mortality is estimated at 51% in patients with bone marrow transplants

62 Rapid diagnostic assays performed on respiratory specimens are available commercially(nasal Wash, throat swab, tracheal aspirate, BAL specimens) Hep-2 cells show typical colony formation, confirmed with immunofluorescent staining Antigen detection tests and culture are generally reliable RT-PCR assays are now commercially available for RSV. The sensitivity of these assays often exceeds the sensitivity of virus isolation and antigen detections methods. Serologic tests are less frequently used for routine diagnosis. Although useful for seroprevalence and epidemiologic studies

63 Overview of diagnostic methods In general, diagnostic tests can be grouped into 3 categories.: (1) direct detection (2) indirect examination (virus isolation) (3) serology

64 Electron Microscopy morphology Light microscopy histological appearance - e.g. inclusion bodies Antigen detection immunofluorescence, ELISA etc. Molecular techniques for the direct detection of viral genomes

65 Cell Culture - cytopathic effect, haemadsorption, confirmation by neutralization, interference, immunofluorescence etc. Eggs pocks on CAM - haemagglutination, inclusion bodies Animals disease or death confirmation by neutralization

66 Detection of rising titres of antibody between acute and convalescent stages of infection, or the detection of IgM in primary infection. Classical Techniques 1. Complement fixation tests (CFT) 2. Haemagglutination inhibition tests 3. Immunofluorescence techniques (IF) 4. Neutralization tests 5. Single Radial Haemolysis Newer Techniques 1. Radioimmunoassay (RIA) 2. Enzyme linked immunosorbent assay (EIA) 3. Particle agglutination 4. Western Blot (WB) 5. Recombinant immunoblot assay (RIBA), line immunoassay (Liatek) etc.